1. Field of the Invention
The present invention relates to a so-called hot process technique utilizing a thermo-chemical reaction of a manufacturing process of a semiconductor device. More particularly, the present invention relates to an apparatus for manufacturing a semiconductor device for use in a hot process, for example, an apparatus for manufacturing a semiconductor device such as an oxidization furnace, an annealing furnace, a CVD furnace, or an RTP furnace and an apparatus and method of controlling the same, a method of manufacturing a semiconductor device using the same, and a method and apparatus for simulating a manufacturing process of a semiconductor device.
2. Description of the Related Art
In recent years, with the miniaturization of a variety of electronic circuits provided in a semiconductor device, there has been a growing demand for improvement of precision in a process of manufacturing a semiconductor device. In particular, higher precision is demanded in a manufacturing process utilizing a thermo-chemical reaction generally called a hot process. This hot process includes the step of forming a variety of thin films such as an insulating film, or alternatively, adjusting a scattering length of distribution of impurities when the impurities are implanted in a semiconductor.
As an example of a general hot process, an oxidizing process carried out when a thin film such as an insulating film is formed on a semiconductor substrate will be described with reference to a flow chart shown in FIG. 32.
First, as initial settings, a variety of parameters such as, gas temperature, gas flow rate and oxidization time when oxidization processing is carried out are inputted to a control computer for controlling a state of the inside an oxidization furnace that serves as a processing chamber in which oxidization processing is carried out. After these parameters have been inputted, a start signal is inputted to the control computer, whereby the start signal is transmitted from the control computer to the oxidization furnace. Then, oxidization processing is started based on the initial settings. Specifically, a series of processes such as bringing a substrate into the oxidization furnace, increasing a temperature, maintaining a temperature, introducing oxidization gas, gas change, reducing a temperature, and bringing a substrate to the outside the oxidization furnace is carried out in accordance with the initial setting values and preset process sequence.
Having checked that these processes have been carried out smoothly in accordance with the process sequence, the control computer transmits a stop signal to the oxidization furnace. The oxidization furnace having received the stop signal terminates oxidization processing. Then, a film thickness monitor installed inside or outside the oxidization furnace checks whether or not the thus-formed thin film has a desired film thickness. When the thin film is formed to have the desired film thickness, next processing is carried out based on the initial settings identical to the previous settings. Otherwise, the previous initial settings are modified, and next processing is carried out.
In general, as the control precision for executing the hot process is higher, it becomes more difficult to ignore the effects of turbulence of the atmosphere inside or outside the processing chamber in which the hot process is carried out, which is a so called disturbance on precision of control. Namely, in order to execute the hot process to be controlled with high precision, it is required to properly set the process to a normal state considering an effect caused by such disturbance. The disturbance used here includes, for example, change in pressure, temperature, or humidity outside the processing chamber as well as change in pressure, temperature, or humidity of the inside the processing chamber to which the semiconductor device is exposed.
However, as described previously, an effect caused by such disturbance is not considered at all in settings to be provided in accordance with the process sequence in which a series of processes is predetermined. For example, when a series of oxidization processes is repeatedly carried out based on the same settings, i.e., when a series of oxidization processings is carried out in a so-called batch scheme, an effect of the previous batch processing upon the next batch processing is not considered at all. For example, the temperature in the oxidization furnace after the previous patch processing has an effect on a work of increasing or reducing the temperature of the inside the oxidization furnace when the next batch processing is carried out. Specifically, due to the heat remaining in the oxidization furnace after the previous batch processing, the actual temperature in the oxidization furnace while the next batch processing is carried out deviates from a target temperature initially set when the next batch processing is started.
In addition, irrespective of a processing scheme, if a voltage applied to the control computer slightly changes, a flow rate of gas to be introduced into the oxidization furnace is different from the set quantity. It is generally impossible to precisely control the above disturbance by using a control computer. In the above settings, a dispersion in film thickness caused by an uncontrollable disturbance of the inside the oxidization furnace is not considered at all. Similarly, a dispersion in film thickness caused by an uncontrollable disturbance of the outside the oxidization furnace such as atmospheric pressure is not considered at all.
In order to consider the effect of the disturbance on the film thickness of an insulating film or scattering of impurities, it is required to carry out computation or simulation concerning an oxidization reaction or deposition process, or alternatively, process of scattering impurities. As the art concerning a simulation apparatus for carrying out such simulation, there is disclosed the art of comparing actual manufacturing data with simulation data in inventions proposed in Jpn. Pat. Appln. KOKAI Publication No. 8-55145, or alternatively, in Jpn. Pat. Appln. KOKAI Publication No. 11-288856.
However, an object of comparing manufacturing data with simulating data carried out in the inventions of Jpn. Pat. Appln. KOKAI Publication No. 8-55145 or No. 11-288856 is to provide simulation itself with high precision or to obtain correlation with actual manufacturing data. Namely, both of these inventions are not considered in view of improving the precision of process control such as modifying the manufacturing conditions or manufacturing parameters in order to execute the manufacturing process in a normal state. In addition, neither of these inventions carries out computation assuming disturbance. Thus, it is impossible to carry out computation considering a dispersion caused by disturbance or an error caused by such disturbance. Therefore, of course, the inventions of Jpn. Pat. Appln. KOKAI Publication No. 8-55145 and No. 11-288856 fail to disclose a method of modifying a dispersion or error in film thickness caused by an uncontrollable disturbance inside or outside a processing system as a dispersion or error of each process.